1. Field of the Invention
This invention generally relates to wheel substitutes for land vehicles, and more particularly, to slide bar suspension systems used in snowmobile endless track suspensions.
2. Description of Related Art
In one form of tracked snowmobiles, where an endless track contacts the snow or ground surface and moves the snowmobile, a slide rail in the snowmobile's suspension transfers the weight of the snowmobile to the ground surface by slidingly contacting the endless track to press the endless track against the ground.
Snowmobiles have over the years become heavier, faster, and more powerful, and therefore slide rails on modern snowmobiles are subject to greater mechanical and heat stresses than in past years. Slide rails are the component of snowmobiles which bear the weight of the snow sled inside of the track. The track rotates around the snowmobile suspension. The snowmobile suspension typically has two slide rails running lengthwise with the track. The track slides under the slide rails and contacts the ground surface. In addition, these stresses are magnified when snowmobiles are operated under adverse conditions, such as, on surfaces where there is no snow or water to cool and lubricate the interface between the slide rail and the endless track, or on surfaces which cause debris such as dirt, sand, and gravel to contaminate the interface between the slide rail and the endless track.
The concept of using plastic to form a wear blade inserted between a snowmobile slide rail and an endless track is known in the art. In particular, U.S. Pat. No. 3,770,330 to Bombardier discloses a replaceable wear blade attached to a snowmobile slide rail. The endless track slides against the wear blade. The replaceable wear blade of Bombardier is formed from a synthetic resin, including synthetic plastics such as polytetrafluoroethylene (PTFE), nylon, polyurethane and ultra high density polyethylene.
U.S. Pat. No. 3,820,858 to Reeve, which discloses a track lubrication system useable with snowmobiles, discloses slide rails formed of or covered with a plastic-like or slippery material such as polytetrafluoroethylene (PTFE).
One conventional slide rail system in current commercial use incorporates a Hyfax-type slider, manufactured by several different companies. One such company is Garland Industries, P.O. Box 538, Saco, ME, 04072. This Hyfax-type slider comprises a pair of sliders which are three (3) to five (5) foot pieces of ultra high molecular weight plastic (UHMW), which are attached to the slide rails so they run lengthwise with the endless track. These sliders press the endless track against the ground surface, so that as the endless track rotates, it slides under the pair of sliders.